include/standard-headers/linux/virtio_blk.h

   1 #ifndef _LINUX_VIRTIO_BLK_H
   2 #define _LINUX_VIRTIO_BLK_H
   3 /* This header is BSD licensed so anyone can use the definitions to implement
   4  * compatible drivers/servers.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of IBM nor the names of its contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE. */
  28 #include "standard-headers/linux/types.h"
  29 #include "standard-headers/linux/virtio_ids.h"
  30 #include "standard-headers/linux/virtio_config.h"
  31 #include "standard-headers/linux/virtio_types.h"
  32
  33 /* Feature bits */
  34 #define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */
  35 #define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */
  36 #define VIRTIO_BLK_F_GEOMETRY   4       /* Legacy geometry available  */
  37 #define VIRTIO_BLK_F_RO         5       /* Disk is read-only */
  38 #define VIRTIO_BLK_F_BLK_SIZE   6       /* Block size of disk is available*/
  39 #define VIRTIO_BLK_F_TOPOLOGY   10      /* Topology information is available */
  40 #define VIRTIO_BLK_F_MQ         12      /* support more than one vq */
  41 #define VIRTIO_BLK_F_DISCARD    13      /* DISCARD is supported */
  42 #define VIRTIO_BLK_F_WRITE_ZEROES       14      /* WRITE ZEROES is supported */
  43
  44 /* Legacy feature bits */
  45 #ifndef VIRTIO_BLK_NO_LEGACY
  46 #define VIRTIO_BLK_F_BARRIER    0       /* Does host support barriers? */
  47 #define VIRTIO_BLK_F_SCSI       7       /* Supports scsi command passthru */
  48 #define VIRTIO_BLK_F_FLUSH      9       /* Flush command supported */
  49 #define VIRTIO_BLK_F_CONFIG_WCE 11      /* Writeback mode available in config */
  50 /* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
  51 #define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
  52 #endif /* !VIRTIO_BLK_NO_LEGACY */
  53
  54 #define VIRTIO_BLK_ID_BYTES     20      /* ID string length */
  55
  56 struct virtio_blk_config {
  57         /* The capacity (in 512-byte sectors). */
  58         __virtio64 capacity;
  59         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  60         __virtio32 size_max;
  61         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  62         __virtio32 seg_max;
  63         /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
  64         struct virtio_blk_geometry {
  65                 __virtio16 cylinders;
  66                 uint8_t heads;
  67                 uint8_t sectors;
  68         } geometry;
  69
  70         /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
  71         __virtio32 blk_size;
  72
  73         /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
  74         /* exponent for physical block per logical block. */
  75         uint8_t physical_block_exp;
  76         /* alignment offset in logical blocks. */
  77         uint8_t alignment_offset;
  78         /* minimum I/O size without performance penalty in logical blocks. */
  79         __virtio16 min_io_size;
  80         /* optimal sustained I/O size in logical blocks. */
  81         __virtio32 opt_io_size;
  82
  83         /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
  84         uint8_t wce;
  85         uint8_t unused;
  86
  87         /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
  88         __virtio16 num_queues;
  89
  90         /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */
  91         /*
  92          * The maximum discard sectors (in 512-byte sectors) for
  93          * one segment.
  94          */
  95         __virtio32 max_discard_sectors;
  96         /*
  97          * The maximum number of discard segments in a
  98          * discard command.
  99          */
 100         __virtio32 max_discard_seg;
 101         /* Discard commands must be aligned to this number of sectors. */
 102         __virtio32 discard_sector_alignment;
 103
 104         /* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */
 105         /*
 106          * The maximum number of write zeroes sectors (in 512-byte sectors) in
 107          * one segment.
 108          */
 109         __virtio32 max_write_zeroes_sectors;
 110         /*
 111          * The maximum number of segments in a write zeroes
 112          * command.
 113          */
 114         __virtio32 max_write_zeroes_seg;
 115         /*
 116          * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the
 117          * deallocation of one or more of the sectors.
 118          */
 119         uint8_t write_zeroes_may_unmap;
 120
 121         uint8_t unused1[3];
 122 } QEMU_PACKED;
 123
 124 /*
 125  * Command types
 126  *
 127  * Usage is a bit tricky as some bits are used as flags and some are not.
 128  *
 129  * Rules:
 130  *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
 131  *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
 132  *   and may not be combined with any of the other flags.
 133  */
 134
 135 /* These two define direction. */
 136 #define VIRTIO_BLK_T_IN         0
 137 #define VIRTIO_BLK_T_OUT        1
 138
 139 #ifndef VIRTIO_BLK_NO_LEGACY
 140 /* This bit says it's a scsi command, not an actual read or write. */
 141 #define VIRTIO_BLK_T_SCSI_CMD   2
 142 #endif /* VIRTIO_BLK_NO_LEGACY */
 143
 144 /* Cache flush command */
 145 #define VIRTIO_BLK_T_FLUSH      4
 146
 147 /* Get device ID command */
 148 #define VIRTIO_BLK_T_GET_ID    8
 149
 150 /* Discard command */
 151 #define VIRTIO_BLK_T_DISCARD    11
 152
 153 /* Write zeroes command */
 154 #define VIRTIO_BLK_T_WRITE_ZEROES       13
 155
 156 #ifndef VIRTIO_BLK_NO_LEGACY
 157 /* Barrier before this op. */
 158 #define VIRTIO_BLK_T_BARRIER    0x80000000
 159 #endif /* !VIRTIO_BLK_NO_LEGACY */
 160
 161 /*
 162  * This comes first in the read scatter-gather list.
 163  * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
 164  * this is the first element of the read scatter-gather list.
 165  */
 166 struct virtio_blk_outhdr {
 167         /* VIRTIO_BLK_T* */
 168         __virtio32 type;
 169         /* io priority. */
 170         __virtio32 ioprio;
 171         /* Sector (ie. 512 byte offset) */
 172         __virtio64 sector;
 173 };
 174
 175 /* Unmap this range (only valid for write zeroes command) */
 176 #define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP      0x00000001
 177
 178 /* Discard/write zeroes range for each request. */
 179 struct virtio_blk_discard_write_zeroes {
 180         /* discard/write zeroes start sector */
 181         uint64_t sector;
 182         /* number of discard/write zeroes sectors */
 183         uint32_t num_sectors;
 184         /* flags for this range */
 185         uint32_t flags;
 186 };
 187
 188 #ifndef VIRTIO_BLK_NO_LEGACY
 189 struct virtio_scsi_inhdr {
 190         __virtio32 errors;
 191         __virtio32 data_len;
 192         __virtio32 sense_len;
 193         __virtio32 residual;
 194 };
 195 #endif /* !VIRTIO_BLK_NO_LEGACY */
 196
 197 /* And this is the final byte of the write scatter-gather list. */
 198 #define VIRTIO_BLK_S_OK         0
 199 #define VIRTIO_BLK_S_IOERR      1
 200 #define VIRTIO_BLK_S_UNSUPP     2
 201 #endif /* _LINUX_VIRTIO_BLK_H */